There is always low frequency noise present in any ambient quiet background and it can be produced by a variety of man-made sources, including machinery and transport and natural sources such as the sea, wind and thunder. It has been repeatedly shown by measurements of wind turbine noise undertaken in the UK, Denmark, Germany and the USA over the past decade, and accepted by experienced noise professionals, that the levels of low frequency noise and vibration radiated from modern, upwind configuration wind turbines are at a very low level, so low that they lie below the threshold of perception.

The old fashioned windmill is viewed with nostalgia, and some people prefer the look of them to that of their modern counterparts. Just because wind turbines are modern, it doesn't mean they won't look just as good over time.

A modern wind turbine is simply an improved windmill. Every aspect of their design has been optimised, making them far more efficient than old style windmills at generating electricity. To make them look more old-fashioned would just result in more expensive electricity.

We will need a mix of both onshore and offshore wind energy to meet the UK's challenging targets on climate change. At present, onshore wind is more economical than development offshore. Furthermore, offshore wind farms take longer to develop, as the sea is inherently a more hostile environment. To expect offshore to be the only form of wind generation allowed would therefore be to condemn us to miss our renewable energy targets and commitment to tackle climate change.

Wind farming is popular with farmers, because their land can continue to be used for growing crops or grazing livestock. Sheep, cows and horses are not disturbed by wind turbines.

The first wind farm built in the UK, Delabole, has a stud farm and riding school, and the farmer, Peter Edwards, often rides around the wind farm on his horse.

The comparison of energy used in manufacture with the energy produced by a power station is known as the 'energy balance'. It can be expressed in terms of energy 'pay back' time, i.e. as the time needed to generate the equivalent amount of energy used in manufacturing the wind turbine or power station.

The average wind farm in the UK will pay back the energy used in its manufacture within six to eight months, this compares favourably with coal or nuclear power stations, which take about six months.

Wind energy is one of the safest energy technologies. It is a matter of record that no member of the public has ever been injured during the normal operation of a wind turbine, with over 25 years operating experience and with more than 70,000 machines installed around the world.

The towers are mostly tubular and made of steel, generally painted light grey. The blades are made of glass-fibre reinforced polyester or wood-epoxy. They are light grey because this is the colour which is most inconspicuous under most lighting conditions. The finish is matt, to reduce reflected light.

The simplest way to think about this is to imagine that a wind turbine works in exactly the opposite way to a fan. Instead of using electricity to make wind, like a fan, turbines use the wind to make electricity.

Almost all wind turbines producing electricity consist of rotor blades which rotate around a horizontal hub. The hub is connected to a gearbox and generator, which are located inside the nacelle. The nacelle is the large part at the top of the tower where all the electrical components are located.

The wind is a diffuse form of energy, in common with many renewable sources. A typical wind farm of 20 turbines might extend over an area of 1 square kilometre, but only 1% of the land area would be used to house the turbines, electrical infrastructure and access roads; the remainder can be used for other purposes, such as farming or as natural habitat.

To obtain 10% of our electricity from the wind would require constructing around 12,000 MW of wind energy capacity. Depending on the size of the turbines, they would extend over 80,000 to 120,000 hectares (0.3% to 0.5% of the UK land area). Less than 1% of this (800 to 1,200 hectares) would be used for foundations and access roads, the other 99% could still b used for productive farming. For comparison, between 288,000 to 360,000 hectares (1.2-1.5% of the UK land area) is covered by roads and some 18.5 million hectares (77%) are used for agriculture.

A wind turbine typically lasts around 20-25 years. During this time, as with a car, some parts may need replacing.

The very first of the mass-produced turbines celebrated its 20th birthday in May 2000. The Vestas 30kW machine has operated steadily throughout its lifetime, with none of the major components needing to be replaced.

The way that a local authority wishes to have a wind farm decommissioned should be covered by clauses in its planning permission. These clauses typically require all visible traces of the wind farm to be removed. This takes care of the turbines. Service tracks, if there are any, could be removed, although it may be best to leave them. Obviously each case is different, depending upon the size and geography of the development. Developers will then comply with these clauses.

The concrete bases could be removed, but it may be better to leave them under the ground, as this causes less disturbance. If so, they would be covered with peat, stone or other indigenous material, and the site returned as closely as practicable to its original state. The turbine itself will often have a scrap value which will cover the costs of such ground restoration.

Wind energy technology is essential reversible, and compared to the problems associated with decommissioning a nuclear power station, or a coal or gas fired plant, decommissioning a wind farm is straight forward and simple.

People often wonder why there aren't more blades on wind turbines. The optimum number of blades for a wind turbine depends on the job the turbine has to do. Turbines for generating electricity need to operate at high speeds, but do not need much torque or turning force. These machines generally have three or two blades. On the other hand, wind pumps operate with plenty of torque but not much speed and therefore have many blades.

The majority of modern wind turbines have three blades, as this design has been found to have a greater aesthetic appeal. The disadvantage is that each blade will add to the overall cost and wieght and can be more difficult to install, particularly offshore.

Two bladed machines are cheaper and lighter, with higher running speeds, which reduces the cost of the gearbox, and they are easier to install. However two bladed machines can be noisier and are not as visually attractive, appearing 'jerky' when they turn. The engineering ideal would be to have only one blade, and some one bladed early prototypes were developed, but didn't stand the test of time.

A modern wind turbine produces electricity 70-85% of the time, but it generates different outputs dependent on wind speed. Over the course of a year, it will generate about 30% of the theoretical maximum output. This is known as its load factor. The load factor of conventional power stations is on average 50%.

It is cheaper to save electricity than to generate it, by whatever method. The latest information on how much it costs to save electricity is available from the Energy Savings Trust. In their Energy Efficiency Standards of Performance Review, they cited the cost of energy efficiency measures as costing around 1.3 pence per kilowatt hour (per unit). The cost of wind energy is currently around 2.4 pence per unit. However, to combat climate change, the UK will need a mix of both renewable energy technologies and energy efficiency measures.

One 1.8 MW wind turbine at a reasonable site would produce over 4,7 million units of electricity each year, enough to meet the annual needs of over 1,000 households, or to run a computer for over 1,620 years.